Recently, as a data recording medium for storing information, a hard disk drive unit (hereinafter referred to as a HDD unit) is being commonly used. In the HDD unit, a plurality of magnetic recording disks (hereinafter referred to as a disk) is provided, and a read/write head is positioned on a desired track defined on the disk for recording or reading information on/from the disk. A plurality of tracks is provided on the disk of the HDD unit, and each track is divided into data sectors (hereinafter referred to as sectors) of 128,256,512 (bytes), etc., with each sector given an identifier (so-called sector ID) representing itself.
In a conventional HDD unit, to improve the reliability of recorded data, a sector ID is recorded for every sector. This sector ID is used for an identification of the position on the disk. When reading or writing from/on a disk, this sector ID is referred to for identifying the data position. Since the sector ID must be referred to in each sector, the ID must be written in each sector. For this ID region, the user data region is reduced.
Recently, for increasing the user data region, an ID-less or headerless architecture for a disk was proposed. The headerless disk has a new sector format. In this new format, the ID region is not provided for each sector and no ID region is needed for recording information. A headerless disk architecture is described in IBM's U.S. Pat. No. 5,438,559.
In a headerless disk, the physical position (ABA: Absolute block Address) and the logical position (LBA: Logical Block Address) on the disk are previously made to correspond to each other and stored in a memory, and from this correspondence relationship, the read/write head is positioned on a desired track of the disk to perform the information recording on the disk or the information reading from the disk. However, in the conventional HDD unit provided with the NO.sub.-- ID disk, the read/write head is positioned by using the above mentioned physical positions (ABA) which correspond to a logical position (LBA) on one-to-one basis. This address conversion procedure for retrieving the physical position from the logical position is executed independently from the data reading or writing operation, so the data write or read operation can be started without recognizing that the head is accurately positioned or not. Such an error can happen when an external factor such as a HDD vibration occurs.
In view of the above fact, it is the object of the present invention to provide a data processing method and a system which can improve the reliability of the data stored on a disk without reducing the capacity.